Adjustable and replaceable lateral guides for telescopic crane boom

ABSTRACT

Longitudinally spaced pairs of lateral guides are mounted on the relatively fixed section of a telescopic crane boom adjacent to the solid bottom chord of the movable section of the boom. The lateral guides are constrained against movement with the movable boom section by key or holder elements and the guides are adjustable laterally to establish an initial running clearance and are subsequently adjustable to compensate for wear. The guides are easily replaceable when necessary.

iinited States Patent 1191 Sterner July 31, 1973 [54] ADJUSTABLE AND REPLACEABLE 2,890,134 6/1959 Mullin i. 151/33 LATERAL GUIDES FOR TELESCOPIC 2,804,949 9/1957 Woolslayer et a1 5 2/118 3,285,431 11/1966 Butcher .1 214/141 CRANE BOOM 3,469,058 9/1969 OConnor 308/3 R [75] Inventor: Russell L. Sterner, Greencastle, Pa. 3,587,886 6/1971 Gano 52/118 [73] Assignee: Walter Kidde & Company, Inc.,

nmary xammer l'lCe aw, 1'. Clifton, NJ. P E P C F J [22] Filed Oct 12 1971 Att0rneyRupert J. Brady et a1. a

[21] Appl. No.: 187,969 [57] ABSTRACT Longitudinally spaced pairs of lateral guides are [52] Cl 52/632 52,118 L mounted on the relatively fixed section of a telescopic crane boom adjacent to the solid bottom chord of the glz' y' g 2 movable section of the boom. The lateral guides are I 0 can 08/3 3 constrained against movement with the movable boom section by key or holder elements and the guides are adjustable laterally to establish an initial running clear- [56] References Clted ance and are subsequently adjustable to compensate UNITED STATES PATENTS for wear. The guides are easily replaceable when neces- 3,537,762 11/1970 Lodige 308/3 R sary. 3,620,579 ll/l97l Brown et al... 308/3 R 2,719,761 10/1955 Bonnafe 308/3 A 9 Claims, 10 Drawing Figures ADJUSTABLE AND REPLACEABLE LATERAL GUIDES FOR TELESCOPIC CRANE BOOM The need for lateral guides or wear pads between relatively movable telescopic sections of crane booms has been recognized in the prior art. Generally, in the past, if two boom sections were misaligned, they were completely separated in the shop and shims were welded into place as lateral guides by a cut-and-try method. Satisfactory adjustment or repair could not generally be done in the field.

Prior US. Pat. No. 3,587,886, issued 'to John W. Gano, for example, proposes the use of adjusting inserts or shims in one form of crane boom assembly. The patented construction is relatively complex and re quires the addition or subtraction of shims in the assembly to produce the necessary adjustments.

One of the principal objects of the present invention is to avoid completely the use of shims and the accompanying inconvenience of adding and substracting shims to effect adjustment and compenstate for wear. In lieu of shims and other prior art expedients, the present invention proposes the use of adjustable lateral guides between pairs of relatively movable boom sections, which guides are associated with screw adjustors or operators which enable an initial fine adjustment to be achieved as well as any number of subsequent adjustments to compensate for wear. These adjustments can be made quickly and easily in the field without the necessity for removing cover plates, housings or the like. When required, after very long periods of usage, the lateral guides can be replaced economically and with a minimum of work. The adjustable guides of the invention are far superior to shims, not onlyin convenience, but in establishing a fine degree of adjustment and a smaller running clearance between boom sections than has heretofore been feasible.

In accordance with the invention, the readily adjustable lateral guides are brought to bear directly on the longitudinal edges of the bottom chord of the movable boom section, which chord can be manufactured straight and with a highly uniform width. Additionally, any serious lateral deflection of the movable boom section side walls would be avoided since the guides do not engage the relatively thin side walls but only the sturdy and solid bottom chord. The lateral guides which are customarily formed of bronze are restrained against vertical movement and longitudinal movement with the movable boom section by steel key or holding elements. The boom sections are suitably reinforced adjacent the adjustable lateral guides to absorb the lateral forces transmitted through the guides and to assure efficient operation of the guides. The adjusting screws for the guides are securely locked in selected positions.

The lateral guides of the invention are utilized in two sets or pairs spaced apart longitudinally on the relatively fixed boom section. One pair of lateral guides is arranged at the outer end of the fixed boom section and a second pair is arranged a proper distance rearwardly to engage the sides of the movable boom section when the latter is fully extended. This arrangement provides for proper alignement of the fully extended section within close limits. With only a single set of guides or pads on the fixed boom section at the forward end thereof, there would be no alignement means for a fully extended movable boom section. Both pairs of lateral guides have the same lateral adjustment capability and relative ease of replacement when necessary. Both are securely lockable, sturdy in construction, compact and require minimum structural modification to install on existing crane booms. The lateral guides are particularly applicable to trapezoidal booms having a wide bottom chord with straight longitudinal edges.

Other features and advantages of the invention will appear to those skilled in the art during the course of the following description.

BRIEF DESCRIPTION OF DRAWING FIGURES FIG. 1 is a fragmentary side elevation of a telescopic crane boom equipped with lateral guides in accordance with the invention.

FIG. 2 is an enlarged fragmentary side elevation of one of a forward pair of lateral guides mounted on a relatively fixed boom section.

FIG. 3 is a fragmentary transverse vertical section taken on line 3-3 of FIG. 2.

FIG. 4 is a similar section taken on line 44 of FIG. 2.

FIG. 5 is a fragmentary longitudinal vertical section taken on line 5-5 of FIG. 3.

FIG. 6 is an enlarged fragmentary side elevation of one of a pair of rear lateral guides and associated parts.

FIG. 7 is a fragmentary vertical section taken on line 7--7 of FIG. 8.

FIG. 8 is a fragmentary transverse vertical section taken on line 8-8 of FIG. 6.

FIG. 9 is a similar section taken on line 9-9 of FIG.

FIG. 10 is a fragmentary plan view of the boom in FIG. 1 on a reduced scale.

DETAILED DESCRIPTION Referring to the drawings in detail wherein like numerals designate like parts throughout, the numerals l0 and 11 designate, respectively, a relatively fixed and a movable boom section forming components of a plural section telescopic construction crane boom or the like. The invention is applicable to any telescoping relatively movable pair of boom sections to provide proper lateral guidance during extension and retraction of the boom. The drawings depict telescoping boom sections which are trapezoidal in cross section, as shown in FIGS. 3 and 4 and 8 and 9, but the guides can also be used with fabricated rectangular cross sectioned booms.

The movable boom section 1 l embodies a sturdy bottom chord 12 having a straight longitudinal edge 13 which is spaced laterally outwardly of the inclined side wall 14 of boom section 11 on each side of the boom. It is feasible to maintain the edges 13 of the bottom chord 12 straight and true and in parallel relation during manufacturing. Consequently, the adjustable lateral guides of thepresentinvention maybe utilized to the fullest advantage in maintaining the smallest possible running clearance between a pair of interfitting boom sections.

The outer or relatively fixed boom section 10 which is also trapezoidal in cross section has an underslung support collar 15 of heavily reinforced construction around its open forward end including sturdy side plates 16 which overlie the relatively thinner inclined side walls 17 of boom section 10. Directly below the bottom chord 12 of boom section 11 and underneath each side wall 14 the collar 15 contains wear pads 18, seated in recesses of holder blocks 19, in turn supported by spherically curved rocker bearings 20, seated on fixed blocks 21 welded inside of the collar structure.

Each forward lateral guide comprises a preferably bronze guide element or pad 22 having a vertical abut,- ment face 23 directly slidably contacting the straight edge 13 of bottom chord 12. The outer side face 24 of the pad or element 22 is inclined parallel to the adjacent wall 17 of boom section 10. The bottom of the pad may rest on an internal web 25 of the collar 15, as shown, and the inner lower corner of the pad is notched at 26 to provide clearance for movement of the rockably mounted holder or block 19. As best shown in FIG. 5, the pad 22 is notched as at 27 in its upper edge to receive a restraining and locating key 28 which prevents vertical as well as longitudinal movement of the pad or guide element 22. Were it not for this restraining key, the element 22 could be displaced by movement of the boom section 11 longitudinally or by possible vertical vibrations since the element 22 is a floating element and unrestrained except by the key 28.

Each lateral guide assembly further embodies an exterior heavy bracket 29 welded around its margin to the collar as indicated at 30. This heavy bracket serves to absorb the lateral forces transmitted through the guide or pad 22 and also provides additional thickness for the screw-threads of a pair of adjusting screws 31 for each element 22. The forward ends of screws 31 bear directly against the faces 24 of the pads 22 to effect lateral adjustment of the latter and thus establish a desired minimum operating clearance between the boom sections 10 and 11. The adjusting set screws 31 are spaced apart sufficiently, FIG. 5, to engage the pads 22 near their opposite ends and on opposite sides of the key 28. The screws 31 are locked in position by sturdy wires 32 so that a given adjustment of the lateral guides will be maintained precisely.

Each key 28 is securely clamped to the side wall 17 by a pair of screws 33 located above and between the adjusting screws 31 and passing through registering openings in each bracket 29 and plate 16.

It may now be seen that each pad or guide element 22 may be precisely adjusted laterally relative to the straight edge 13 from the outside of the boom without removing any cover plate or the like and without the necessity for separating adjacent boom sections. The use of awkward shims and cut-and-try methods are completely eliminated by the invention and the adjutment or replacement of the guide elements 22 by any field mechanic is rendered feasible by the invention.

The invention as previously noted also embodies a rear pair of adjustable and replaceable lateral guides having the basic characteristics of the forward pair of guides although being specifically different in details of construction. The details of one rear lateral guide are shown in FIGS. 6 to 9 of the drawings.

In these figures, preferably bronze lateral guide elements or pads 34 are positioned in adjustable sliding contact with the straight edges 13 of bottom chord 12. The bottoms of the pads 34 rest directly upon the bottom chord 35 of the outer relatively fixed boom section 10. The otherwise floating pads 34 are constrained against vertical and longitudinal movement by steel holders 36 having rectangular recesses 37 in their inner faces and bottoms to receive the elongated block-like pads 34 with a small degree of clearance. Each holder 36 is equipped with a pair of self-locking adjusting set screws 38 for the elements 34 and these self-locking screws are of the type having a locking insert of nylon or some similar material interrupting the screw threads thereof. The set screws 38 bear directly on the outer faces of the pads 34 near their opposite ends.

Mounting brackets 39 are welded to the holders 36 around the margins of the latter as shown at 40. These brackets in turn are connected by screws 41 to heavier back-up plates 42 which may be permanently affixed to the side walls 17 of boom section 10 by welding.

The general use or mode of operation of the adjustable rear guide elements 34 is the same as described previously in connection with the forward elements 22. The elements 34 are initially adjusted to a desired running clearance and may be subsequently adjusted by the self-locking screws 38 at any time to compensate for wear or misalignment. The pads or elements 34 are easily replaceable in the field simply by removal of the holders 36 which is accomplished by removal of the several screws 41'. Again, the use of awkward shimming is completely avoided.

When theboom section 11 is fully extended substantially as shown in FIG. 1, the rearward lateral guides allow full lateral guidance and alignment of the rear end of the section 11 to be maintained relative to the section 10. This could not be done if only a single pair of the guide units were employed.

FIG. 10 shows the relative positions of the forward and rear pairs of lateral guide assemblies which have already been described in detail. For convenience of reference and clarity, each forward lateral guide assembly is designated in its entirety by the numeral 43 and each rearward lateral guide assembly is designated by the numeral 44.

The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof but it is recognized that various modifications are possible within the scope of the invention claimed.

I claim:

1. In a crane boom, a pair of telescopically interfitting boom sections, the interior boom section being longitudinally extensible and retractable within the exterior section, the interior boom section having a bottom chord including opposite side parallel straight edges, a pair of lateral guide assemblies on the exterior boom section adjacent the bottom thereof and adjacent said chord and straight edges of the interior boom section, each lateral guide assembly comprising a floating wear pad having an abutment face for guiding engagement with one of said straight edges, retainer means for each wear pad disposed in a substantially vertical plane on the exterior boom section, said retainer means having wall portions in closely spaced relationship with said wear pad, whereby the wear pad is prevented from being displaced longitudinally or vertically with respect to the axis of the boom during longitudinal movements of the interior boom section, and continuously operable lateral adjusting means for each wear pad on the exterior boom section permitting an initial fine adjustment of the wear pads relative to said straight edges and subsequent adjustments of the wear pads as wear occurs.

2. The structure of claim 1, and said continuously operable lateral adjusting means comprising a pair of adjusting set screws for each wear pad on said exterior boom section bearing directly against outer faces of the pads, and means to positively lock the adjuting set screws in selected adjusted positions.

3. The structure of claim 2, and said means to lock the adjusting screws comprising wire locking means.

4. The structure of claim 2, and said lockable adjusting set screw means comprising a pair of spaced selflocking set screws.

5. The structure of claim 4, and said self-locking set screws having threaded engagement in said retainer.

6. The structure of claim 1, and said retainer being detachably secured to the exterior boom section side wall to facilitate removal and replacement of the wear v means comprises holder means, and a recess formed in said holder means for receiving a portion of said wear pad.

9. The structure of claim 1, wherein the wall portions comprise a pair of end walls and a longitudinal wall portion. 

1. In a crane boom, a pair of telescopically interfitting boom sections, the interior boom section being longitudinally extensible and retractable within the exterior section, the interior boom section having a bottom chord including opposite side parallel straight edges, a pair of lateral guide assemblies on the exterior boom section adjacent the bottom thereof and adjacent said chord and straight edges of the interior boom section, each lateral guide assembly comprising a floating wear pad having an abutment face for guiding engagement with one of said straight edges, retainer means for each wear pad disposed in a substantially vertical plane on the exterior boom section, said retainer means having wall portions in closely spaced relationship with said wear pad, whereby the wear pad is prevented from being displaced longitudinally or vertically with respect to the axis of the boom during longitudinal movements of the interior boom section, and continuously operable lateral adjusting means for each wear pad on the exterior boom section permitting an initial fine adjustment of the wear pads relative to said straight edges and subsequent adjustments of the wear pads as wear occurs.
 2. The structure of claim 1, and said continuously operable lateral adjusting means comprising a pair of adjusting set screws for each wear pad on said exterior boom section bearing directly against outer faces of the pads, and means to positively lock the adjuting set screws in selected adjusted positions.
 3. The structure of claim 2, and said means to lock the adjusting screws comprising wire locking means.
 4. The structure of claim 2, and said lockable adjusting set screw means comprising a pair of spaced self-locking set screws.
 5. The structure of claim 4, and said self-locking set screws having threaded engagement in said retainer.
 6. The structure of claim 1, and said retainer being detachably secured to the exterior boom section side wall to facilitate removal and replacement of the wear pad when necessary.
 7. The structure of claim 1 wherein the retainer means comprises key means, and a notch formed in the wear pad for receiving said key means.
 8. The structure of claim 1 wherein the retainer means comprises holder means, and a recess formed in said holder means for receiving a portion of said wear pad.
 9. The structure of claim 1, wherein the wall portions comprise a pair of end walls and a longitudinal wall portion. 